Cholinergic, dopaminergic and insulin receptors gene expression in the cerebellum of streptozotocin-induced diabetic rats: functional regulation with Vitamin D3 supplementation.

The study was to find out the effect of Vitamin D3 supplementation on preventing the altered gene expression of cholinergic, dopaminergic, insulin receptors and GLUT3 gene expression in cerebellum of diabetic rats. Radioreceptor binding assays and gene expression were done in the cerebellum of male Wistar rats. Rota rod has been used to evaluate motor coordination. Our results showed a significantly increased gene expression of dopamine D2, muscarinic M1, M3, alpha7 nicotinic acetylcholine, insulin receptors, acetylcholine esterase, GLUT3 and Vitamin D receptor in the cerebellum of diabetic rats. There was a down-regulation of dopamine D1 receptor. Total dopamine receptor showed a decreased and total muscarinic, muscarinic M1 and M3 receptors showed an increased binding parameter, B(max). Rota rod experiment showed a significant decrease in the retention time on the rotating rod in diabetic while treatment improved retention time near to control. Vitamin D3 and insulin treatment markedly recovered the altered gene expression and binding parameters to near control. Our study showed Vitamin D3 functional regulation through dopaminergic, cholinergic and insulin receptors and glucose transport mechanism through GLUT3 in the cerebellum of diabetic rats which play a major role in neuroprotection in diabetes which has clinical application. 2010 Elsevier Inc. All rights reserved.